App Development for android and IOS - App project

Mobile app project description

I am looking to create both Android and IOS app. I would like to integrate these apps to my already existing web based payroll and invoicing system(laravel).
We send casual nurses (and various other staffs) to hospitals when the hospital is under staffed. When a hospital book a shift, they either email or call us, they tell us what staffs(Nurses/carers/cleaners) they are looking for and for what time and date. We want an app where we can put these shift details(Time, date, location and other details) and the shift is sent to our staffs and if someone accepts to do the shift their name is allocated to that system in the database. So when we create invoice(for facilities) and payrolls(for our staffs) all calculations are done under that persons name. Once the project is in progress, We will provide induction and source code to our invoicing and payroll system for better understanding.
I have attached a hand written requirements for the project please go through that to have an indepth view of the projects.